/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *  
 *    http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License. 
 *  
 */

package org.apache.mina.protocol.dns.io.encoder;

import org.apache.mina.common.IoBuffer;
import org.apache.mina.protocol.dns.messages.RecordClass;
import org.apache.mina.protocol.dns.messages.RecordType;
import org.apache.mina.protocol.dns.messages.ResourceRecord;

/**
 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
 * @version $Rev: 84 $, $Date: 2008-02-22 16:33:48 +0000 (Fri, 22 Feb 2008) $
 */
public abstract class ResourceRecordEncoder implements RecordEncoder {
    public void put(IoBuffer byteBuffer, ResourceRecord record) {
        putDomainName(byteBuffer, record.getDomainName());
        putRecordType(byteBuffer, record.getRecordType());
        putRecordClass(byteBuffer, record.getRecordClass());

        byteBuffer.putInt(record.getTimeToLive());

        putResourceRecord(byteBuffer, record);
    }

    protected abstract void putResourceRecordData(IoBuffer byteBuffer,
            ResourceRecord record);

    protected void putResourceRecord(IoBuffer byteBuffer, ResourceRecord record) {
        int startPosition = byteBuffer.position();
        byteBuffer.position(startPosition + 2);

        putResourceRecordData(byteBuffer, record);

        putDataSize(byteBuffer, startPosition);
    }

    protected void putDataSize(IoBuffer byteBuffer, int startPosition) {
        int endPosition = byteBuffer.position();
        short length = (short) (endPosition - startPosition - 2);

        byteBuffer.position(startPosition);
        byteBuffer.putShort(length);
        byteBuffer.position(endPosition);
    }

    /**
     * <domain-name> is a domain name represented as a series of labels, and
     * terminated by a label with zero length.
     * 
     * @param byteBuffer the IoBuffer to encode the domain name into
     * @param domainName the domain name to encode
     */
    protected void putDomainName(IoBuffer byteBuffer, String domainName) {
        String[] labels = domainName.split("\\.");

        for (String label : labels) {
            byteBuffer.put((byte) label.length());

            char[] characters = label.toCharArray();
            for (char character : characters) {
                byteBuffer.put((byte) character);
            }
        }

        byteBuffer.put((byte) 0x00);
    }

    protected void putRecordType(IoBuffer byteBuffer, RecordType recordType) {
        byteBuffer.putShort(recordType.convert());
    }

    protected void putRecordClass(IoBuffer byteBuffer, RecordClass recordClass) {
        byteBuffer.putShort(recordClass.convert());
    }

    /**
     * <character-string> is a single length octet followed by that number
     * of characters.  <character-string> is treated as binary information,
     * and can be up to 256 characters in length (including the length octet).
     * 
     * @param byteBuffer The byte buffer to encode the character string into.
     * @param characterString the character string to encode
     */
    protected void putCharacterString(IoBuffer byteBuffer,
            String characterString) {
        byteBuffer.put((byte) characterString.length());

        char[] characters = characterString.toCharArray();

        for (char character : characters) {
            byteBuffer.put((byte) character);
        }
    }
}
